An unexpected and persistent increase in global emissions of ozone-depleting CFC-11

Montzka, S. A.; Dutton, G. S.; Yu, Pengfei; Ray, E. A.; Portmann, R. W.; Daniel, J. S.; Kuijpers, L. J. M.; Hall, B. D.; Mondeel, D. J.; Siso, Carolina; Nance, J. D.; Rigby, Matthew; Manning, Alistair J.; Hu, Lei; Moore, F. L.; Miller, Ben; Elkins, James W.

doi:10.1038/s41586-018-0106-2

Cited by 303 publications

(315 citation statements)

References 25 publications

Supporting

Mentioning

280

Contrasting

Unclassified

Order By: Relevance

“…4), but the method used does not provide the regional-level emission estimates needed to identify the causes of this rise. Montzka et al (2018) recently concluded that East Asia was the source.…”

Section: Is the Montreal Protocol Working?mentioning

confidence: 99%

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE)

Prinn

Weiss

Arduini

et al. 2018

Earth Syst. Sci. Data

Self Cite

233

231

View full text Add to dashboard Cite

Abstract. We present the organization, instrumentation, datasets, data interpretation, modeling, and accomplishments of the multinational global atmospheric measurement program AGAGE (Advanced Global Atmospheric Gases Experiment). AGAGE is distinguished by its capability to measure globally, at high frequency, and at multiple sites all the important species in the Montreal Protocol and all the important non-carbon-dioxide (non-CO2) gases assessed by the Intergovernmental Panel on Climate Change (CO2 is also measured at several sites). The scientific objectives of AGAGE are important in furthering our understanding of global chemical and climatic phenomena. They are the following: (1) to accurately measure the temporal and spatial distributions of anthropogenic gases that contribute the majority of reactive halogen to the stratosphere and/or are strong infrared absorbers (chlorocarbons, chlorofluorocarbons – CFCs, bromocarbons, hydrochlorofluorocarbons – HCFCs, hydrofluorocarbons – HFCs and polyfluorinated compounds (perfluorocarbons – PFCs), nitrogen trifluoride – NF3, sulfuryl fluoride – SO2F2, and sulfur hexafluoride – SF6) and use these measurements to determine the global rates of their emission and/or destruction (i.e., lifetimes); (2) to accurately measure the global distributions and temporal behaviors and determine the sources and sinks of non-CO2 biogenic–anthropogenic gases important to climate change and/or ozone depletion (methane – CH4, nitrous oxide – N2O, carbon monoxide – CO, molecular hydrogen – H2, methyl chloride – CH3Cl, and methyl bromide – CH3Br); (3) to identify new long-lived greenhouse and ozone-depleting gases (e.g., SO2F2, NF3, heavy PFCs (C4F10, C5F12, C6F14, C7F16, and C8F18) and hydrofluoroolefins (HFOs; e.g., CH2 = CFCF3) have been identified in AGAGE), initiate the real-time monitoring of these new gases, and reconstruct their past histories from AGAGE, air archive, and firn air measurements; (4) to determine the average concentrations and trends of tropospheric hydroxyl radicals (OH) from the rates of destruction of atmospheric trichloroethane (CH3CCl3), HFCs, and HCFCs and estimates of their emissions; (5) to determine from atmospheric observations and estimates of their destruction rates the magnitudes and distributions by region of surface sources and sinks of all measured gases; (6) to provide accurate data on the global accumulation of many of these trace gases that are used to test the synoptic-, regional-, and global-scale circulations predicted by three-dimensional models; and (7) to provide global and regional measurements of methane, carbon monoxide, and molecular hydrogen and estimates of hydroxyl levels to test primary atmospheric oxidation pathways at midlatitudes and the tropics. Network Information and Data Repository: http://agage.mit.edu/data or http://cdiac.ess-dive.lbl.gov/ndps/alegage.html (https://doi.org/10.3334/CDIAC/atg.db1001).

show abstract

Section: Is the Montreal Protocol Working?mentioning

confidence: 99%

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE)

Prinn

Weiss

Arduini

et al. 2018

Earth Syst. Sci. Data

Self Cite

233

231

View full text Add to dashboard Cite

show abstract

“…Thus, the IH gradient is an important piece of information that can help to disentangle the influence of emissions from the influence of OH on MCF growth rate variations. This use of the IH gradient for constraining global emissions of anthropogenically emitted gases has also been recognized in previous research (Liang et al (2017); Montzka et al (2018)). …”

Section: Introductionmentioning

confidence: 99%

“…The model incorporates two tracers (MCF and CH 4 ) and 25 consists of two boxes (the troposphere in the NH and in the SH), which are delineated by a fixed equator. The stratosphere is implicitly included in the model through a first-order loss process that is taken to be equal for both hemispheres.…”

Section: Two-box Inversionmentioning

confidence: 99%

“…However, in a two-box set-up, an additional constraint is provided by the IH gradient of MCF. Emission inventories show that MCF emissions are predominantly located in the Northern Hemisphere (NH), whereas OH has a NH to SH ratio that is uncertain, 25 but the ratio has a likely range of 0.85-1.15 (Patra et al, 2014). Therefore, these two processes have a very different effect on the IH gradient of MCF: a parameter implicitly optimized in a two-box model.…”

Section: Introductionmentioning

confidence: 99%

“…The other biases mostly impact the IH gradient of MCF and of CH 4 . For example, 25 we have found that aggregating observations from the NOAA surface network to hemispheric averages results in a systematic overestimate of the true IH gradient (see Figure 3). To sustain this higher IH gradient the inversion will derive emissions that are also too high, and correcting for this bias (by reducing the IH gradient) results in lower CH 4 emissions: a difference of, in this case, 21 Tg/yr (surface sampling bias in Table 3).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Constraints and biases in a tropospheric two-box model of OH

Naus¹,

Montzka²,

Pandey³

et al. 2018

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract.The hydroxyl radical (OH) is the main atmospheric oxidant and the primary sink of the greenhouse gas CH 4 . In two recent studies, constraints on the hydroxyl radical (OH) were derived using a tropospheric two-box model of methyl chloroform (MCF) and CH 4 . When OH variations as derived in this set-up were propagated to the CH 4 budget, the constraints on OH from MCF still allowed for a wide range of CH 4 emission scenarios. This is important, because global CH 4 emissions are generally 5 considered best constrained by the global lifetime of CH 4 , which is determined mainly by OH. Here, we investigate how the use of a tropospheric two-box model in these studies can have affected derived constraints on OH, due to the simplifying assumptions inherent to a two-box model. First, instead of prescribing fixed model parameters for interhemispheric transport, chemical loss rates and loss to the stratosphere, we derive species-and time-dependent quantities from a full 3D transport model simulation. We find significant deviations between the magnitude and time-dependence of the parameters we derive, 10 and the assumptions commonly reported and adopted in literature. Moreover, using output from the 3D model simulations, we investigated differences between the burden seen by the surface measurement network of the National Oceanic and Atmospheric Administration and the true tropospheric burden. Next, we accounted for these biases in a two-box model inversion of MCF and CH 4 , to investigate the impact of the biases on OH constraints.We find that the sensitivity of interannual OH anomalies to the biases is modest (1-2%), relative to the significant uncertain-15 ties on derived OH (5-8%). However, in an inversion where we implemented all four bias corrections simultaneously, we did find a shift to a positive OH trend over the 1994-2015 period. Moreover, the magnitude of derived global mean OH and by extent that of global CH 4 emissions are affected much more strongly by the bias corrections than their anomalies (∼10%). In this way, we identified and quantified direct limitations in the two-box model approach that can possibly be corrected for when a full 3D simulation is used to inform the two-box model. This derivation is, however, an extensive and species-dependent 20 exercise. Therefore, a good alternative would be to move the inversion problem of OH to a 3D model completely. It is crucial to account for the limitations of two-box models in future attempts to constrain the atmospheric oxidative capacity, especially because though MCF and CH 4 behave similarly in large parts of our analysis, it is not obvious that this should be the case for alternative tracers that potentially constrain OH, other than MCF.1 Atmos. Chem. Phys. Discuss., https://doi

show abstract

Relativistic Theory and Ab Initio Simulations of Electroweak Decay Spectra in Medium‐Heavy Nuclei and of Atomic and Molecular Electronic Structure

Morresi

Taioli

Simonucci

2018

Advcd Theory and Sims

View full text Add to dashboard Cite

In this work a novel theoretical and computational method for computing electroweak beta decay spectra of medium and heavy-mass nuclei, as well as the electronic structure of atomic and molecular systems is developed. In particular, starting from the phenomenological electroweak interaction of the Standard Model (SM) of particles, a general expression of the beta decay rate was derived. Relativistic effects are taken into account by solving the many-electron Dirac equation from first-principles. Furthermore, an extension of this approach to include the nucleon-nucleon interaction at the same level of theory of the electronic correlations has been devised. It is shown that post-collisional effects, and to a lesser extent the electronic exchange and correlation, can modify significantly the cross-section only at low energies (<10 keV), while nuclear correlations considerably affect the lineshape of both the absorption and emission spectra particularly in odd-odd nuclear transitions, where the independent particle approximation, on which the nuclear shell model is framed, is more likely to fail. These findings demonstrate the importance of moving beyond the independent particle picture to obtain an accurate description of the experimental data by adding the many-body correlations between the spectator and participator hadrons and leptons involved in the decay. The application of our approach to a number of test cases, such as the modeling of beta decay of 36 Cl, 63 Ni, 129 I, 210 Bi, 241 Pu and of the electron capture of 138 La 3+ , leads to an extremely good agreement with the relevant experimental data. Finally, the extension of this method to atomic and molecular systems by calculating the electronic structures of 138 La 3+ and several isomers (MgCN, MgNC) and molecules (HMgCN, MgCNO, and BrCF 3 ) relevant to astrophysical scenarios is presented. This method, which is capable to deal with both nucleonic and electronic degrees of freedom, has far-reaching implications also in neutrino physics and nuclear astrophysics. 1800086 (23 of 24) www.advancedsciencenews.com www.advtheorysimul.com Keywords Dirac equation, electronic structure simulations, nuclear beta decay, nuclear many-body effects, standard model Hamiltonian

show abstract

An unexpected and persistent increase in global emissions of ozone-depleting CFC-11

Cited by 303 publications

References 25 publications

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE)

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE)

Constraints and biases in a tropospheric two-box model of OH

Relativistic Theory and Ab Initio Simulations of Electroweak Decay Spectra in Medium‐Heavy Nuclei and of Atomic and Molecular Electronic Structure

Contact Info

Product

Resources

About